Impersonal Passive – Structure with That-Clauses

In the structure using that-clauses, you should match the form of the reporting verb to the right
tense, as in the examples below:

a) People think that the summer will be hot. (Present Simple)
It is thought that the summer will be hot. (Present Simple passive of the verb “think”)

b) People thought that the winter was mild. (Past Simple)
It was thought that the winter was mild. (Past Simple passive of the verb “think”)

c) People have suggested that we should handle the climate change urgently. (Present Perfect)
It has been suggested that we should handle the climate change urgently. (Present Perfect passive of the verb “suggest”)

Note that what follows the word “that” remains unchanged.